Conventional upholstery tack strips are made from flat metal (e.g., metal) ribbons by a punch-press operation. Specifically, generally triangularly-shaped nails are formed by punching out correspondingly shaped, partially cut-out sections from the metal ribbon at spaced-apart locations along the ribbon's length and then bending the sections so each is at substantially a right angle relative to the ribbon stock. Thus, the nails remain unitarily attached to the metal ribbon, but project outwardly therefrom.
In use, the metal from which conventional tack strips are made can physically mar and/or abrade the upholstery fabric. For example, the ribbon, if formed from metal, may rust over time which might in turn visibly discolor the fabric. Furthermore, the edges of the metal tack strip may abrade or cut the upholstery fabric. In order to prevent such problems, it has been conventional practice to provide upholstery tack strips with a separate C-shaped plastic sleeve which slides over the tack strip along its length. The plastic sleeve, however, is itself problematic in that it involves a separate manufacturing step to slideably mate it with the tack strip. Furthermore, unless some means are provided to restrict relative lengthwise movement between the metal tack strip and the sleeve, the latter can become separated from the former during use and/or installation.
In our recently issued U.S. Pat. No. 6,537,646 B2 (the entire content of which is expressly incorporated hereinto by reference), novel upholstery tack strips are provided which include a thermoplastic sleeve and a metal ribbon embedded within the sleeve. The sleeve itself includes a plurality of removed material sections forming opposed pairs of sleeve windows, while the metal ribbon integrally includes nail sections which protrude outwardly from the tack strip through respective ones of the sleeve windows. Most preferably, the sleeve is extrusion-coated onto the metal ribbon stock using a cross-head die with a screw extruder. The thus-coated metal strip preform may then be transferred to downstream fabrication operations whereby the sleeve windows and nail portions are formed. Since the nail portions protrude outwardly from the tack strip through the sleeve windows, relative lengthwise slippage between the metal ribbon stock and the sleeve is prevented.
The present invention is directed specifically toward improvements to the upholstery tack strips of the type generally disclosed in our above-cited U.S. Pat. No. 6,537,646 B2. More specifically, according to the present invention upholstery tack strips include a metal ribbon and a thermoplastic sleeve covering at least a portion of the ribbon. The sleeve includes at least one lengthwise removed strip section so as to expose a corresponding lengthwise surface of the metal ribbon. Most preferably, at least one (and advantageously both) edges of the metal ribbon are knurled or serrated so as to present a roughened surface to the sleeve and thereby anchor the metal ribbon to the sleeve and thereby assist in maintaining the relative positioning of the sleeve and metal ribbon. An adhesive may optionally alternatively or additionally be applied to the metal ribbon so as to also assist in anchoring the thermoplastic sleeve thereto. The metal ribbon integrally includes nail sections which protrude outwardly from said tack strip.
These and other aspects and advantages will become more apparent after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.